As archaeological science enters its fifth decade, it is unfortunately still true that many studies in this area neither pose nor answer any question of real archaeological significance. Some individuals, however, have shown a talent for developing new methods to address important archaeological issues. Few have done this better than the South African archaeologist Nikolaas J. van der Merwe.

The son of a school teacher in the remote eastern Cape Province, van der Merwe's career in archaeological science began by chance when in 1958 he won a scholarship, provided by a South African shipping line, to attend Yale University. In 1962 he majored there in physics and minored in anthropology. Yale was then active in the new field of archaeological science, and van der Merwe worked in the radiocarbon laboratory of Minze Stuiver and with the irrepressible geochemist Karl Turekian. A casual remark by the latter to the effect that it ought to be possible to date charcoal-smelted steel by the radiocarbon method was pursued by van der Merwe as his Ph.D. research. This was almost certainly the first dissertation in anthropology to have been funded by NASA, and it was published as The Carbon-14 Dating of Iron (Chicago 1969). Archaeological application of this technique was limited, however, by the large size of the sample required for decay counting. The advent of AMS radiocarbon dating in the 1980s has revived interest in this technique, making it possible to date important innovations in ferrous metallurgy without doing significant damage to valuable museum specimens. This is currently an area of active research by other scholars. Van der Merwe has made other significant contributions to the development of radiocarbon dating, most notably as consultant archaeologist to the Oxford Accelerator Mass Spectrometry Unit in the mid-1980s.

From 1966 to 1974 van der Merwe taught anthropology at the State University of New York at Binghamton and applied his interests in radiocarbon dating and metallurgy within a large field project in his native South Africa. With support from the National Science Foundation, he directed a major program of field survey and excavation focused on pre-industrial mining in the copper ore body at Phalaborwa, then in the earliest stages of destruction by open-pit mining. A major interest during this period was the scientific study of indigenous African mining and metallurgy; subsequently he expanded this interest to include ethnographic work on the last remnants of indigenous iron smelting technology in West and East Africa. His work on this topic, together with that of fellow pioneers Peter Schmidt and Don Avery, was highly influential and has been emulated by their students and colleagues. The result is an exceptionally rich archive of ethnographic and technical data that supplies invaluable analogues for archaeologists to draw upon in interpreting prehistoric metalworking sites worldwide.

In 1974 he moved to head the Department of Archaeology at the University of Cape Town, and his major research interest shifted to the work for which he is now best known. Since the mid-1960s the radiocarbon community in North America had known that 14C dates on corn kernels were systematically younger than those obtained on wood charcoal from the same levels, but could be corrected if the ratios of the stable carbon isotopes 13C and 12C were also measured. By 1970 plant physiologists had shown that the aberrant carbon isotope content of corn and many other tropical grasses resulted from a different mechanism of photosynthesis than that of plants in temperate climate zones. Van der Merwe's brilliant insight came in realizing that in certain circumstances the stable isotope analysis technique offered a means of tracking the spread of cereal agriculture. Since we are what we eat, the adoption of corn as a staple cereal in a temperate environment should result in a marked change in the stable carbon isotope ratios of bone protein (collagen) and bone mineral (apatite) in consumers.

Van der Merwe demonstrated in 1977, after working with J.C. Vogel at the radiocarbon laboratory in Pretoria, that the adoption of corn agriculture in northeastern North America occurred in the later first millennium A.D.—half a millennium later than archaeologists then believed. He subsequently documented the rise of corn agriculture in the Amazon, highland Peru, and Belize, and extended the method to study marine and terrestrial components in the diet of prehistoric coastal peoples in South Africa and Ecuador. Stable isotope analysis has since become a standard method in the study of past diets, and the Cape Town laboratory remains at the cutting edge of research in this area. Van der Merwe and his former students Judy Sealy and Julia Lee-Thorp are also internationally recognized for their research in the field of isotopic ecology and palaeoecology, where they employ stable isotope ratios to infer the diets of organisms from elephants to australopithecines.

In 1988 van der Merwe was appointed the first Landon T. Clay Professor of Scientific Archaeology at Harvard University, but he continues to hold an adjunct appointment at Cape Town and to head the isotope laboratory there. At Harvard he has expanded his research into studies of the provenance of Greek and Roman marbles (a field pioneered by a previous recipient of the Pomerance Medal, Norman Herz).

This account by no means exhausts van der Merwe's contributions to scientific archaeology, but constraints on space preclude discussion of other work. (We cannot however resist mentioning his chromatographic identification of residues in ancient smoking pipes, in the course of which he was licensed by the South African police to possess cannabis!). Few scholars in the field of archaeological science have been as innovative as Nik van der Merwe, and for this the Archaeological Institute of America honors him with the Pomerance Science Medal for 1998